Method and system for dispensing resist solution

ABSTRACT

An apparatus and method for dispensing a solution on a substrate is described in which the solution is dispensed through a solution nozzle assembly while the substrate is rotated. As the solution is dispensed, the solution on the substrate forms a wave front that radially spreads from the substrate center to the substrate edge. The dispensing of the solution is performed in such a way that the solution is dispensed at a radial location substantially equivalent to or less than the radial location of the wave front at any instant in time.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Continuation of and claims the benefit of priorityunder 35 U.S.C. §120 from U.S. Ser. No. 10/880,556, filed Jul. 1, 2004;the entire contents of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a method and system for dispensing amaterial solution on a substrate, and, more particularly, to a methodand system for dispensing a material solution on a substrate in order toreduce the volume of dispensed fluid.

2. Description of the Related Art

In material processing methodologies, pattern etching includes theapplication of a thin layer of light-sensitive material, such asphotoresist, to an upper surface of a substrate that is subsequentlypatterned in order to provide a mask for transferring this pattern tothe substrate during etching. The patterning of the light-sensitivematerial generally involves coating an upper surface of the substratewith a thin film of light-sensitive material, exposing the thin film oflight-sensitive material to a radiation source through a reticle (andassociated optics) using, for example, a micro-lithography system,followed by a developing process during which the removal of theirradiated regions of the light-sensitive material occurs (as in thecase of positive photoresist), or the removal of non-irradiated regionsoccurs (as in the case of negative resist) using a developing solvent.

During the coating process, a substrate is positioned on a substrateholder, and it is rotated at high speed, i.e., several thousand or tensof thousand revolutions per minute (rpm), while resist solution isdispensed on an upper surface of the substrate. When, for example, theresist solution is dispensed at the center of the substrate, the resistsolution spreads radially across the substrate due to centrifugal forcesimposed by the substrate rotation. In order to reduce the costsassociated with resist solution dispensing, the total volume (or shotsize) of resist solution that is dispensed is minimized, which placesgreater emphasis on the design of dispensing parameters (i.e., rotationrate, dispensing rate, resist solution fluid properties, etc.)sufficient to achieve a uniform coating on the substrate.

SUMMARY OF THE INVENTION

One object of the invention is to provide a method and apparatus fordispensing a solution on a substrate that overcomes or reduces problemsof conventional coating systems.

Another object of the present invention is to provide a method andapparatus for dispensing a solution on a substrate using a reduced shotsize.

According to one aspect of the invention, a solution nozzle assembly fordispensing a solution on a substrate is described. The assembly includesone or more nozzles configured to dispense the solution on an uppersurface of the substrate while the substrate is rotated causing thesolution dispensed on the substrate to form a wave front that spreadsradially across the upper surface of the substrate. A controller causesthe one or more nozzles to initially dispense the solution substantiallyat the center of the substrate, and progress to dispense the solution ata radial location substantially equivalent to or less than a radialposition of the wave front at any instant in time.

According to yet another aspect of the invention, a coating system fordispensing a solution on a substrate is described. The system includes acoating chamber; a substrate holder coupled to the coating chamber andconfigured to support the substrate; a drive unit coupled to thesubstrate holder and configured to rotate the substrate holder; and asolution nozzle assembly coupled to the coating chamber and configuredto dispense the solution on the substrate from one or more nozzles inorder to form a wave front that spreads radially across the uppersurface of the substrate. A controller causes the nozzle assembly toinitially dispense the solution substantially at the center of thesubstrate, and progress to dispense the solution at a radial locationsubstantially equivalent to or less than a radial position of the wavefront at any instant in time.

According to yet another aspect of the invention, a method of dispensinga solution on a substrate is described. The method includes rotating thesubstrate; dispensing the solution from a solution nozzle assembly onthe substrate in order to form a wave front that spreads radially acrossthe upper surface of the substrate. The solution initially dispenses atthe center of the substrate, and progresses to dispense at a radiallocation substantially equivalent to or less than a radial position ofthe wave front at any instant in time. The method also includesterminating the dispensing of the solution; and terminating the rotatingof the substrate.

According to yet another object of the invention, a computer readablemedium containing program instructions for execution on a processor,which when executed by the processor cause a coating system to performthe following steps: rotating the substrate; dispensing the solutionfrom a solution nozzle assembly on the substrate in order to form a wavefront that spreads radially across the upper surface of the substrate,wherein the solution initially dispenses at the center of the substrate,and progresses to dispense at a radial location substantially equivalentto or less than a radial position of the wave front at any instant intime; terminating the dispensing of the solution; and terminating therotating of the substrate.

BRIEF DESCRIPTION OF THE DRAWINGS

In the accompanying drawings:

FIG. 1 is a schematic view of a resist solution coating-developingsystem of the present invention including a film forming apparatus;

FIG. 2 presents a coating system for dispensing a solution on asubstrate according to an embodiment of the invention;

FIG. 3 illustrates a method of using the system depicted in FIG. 2;

FIG. 4 presents a coating system for dispensing a solution on asubstrate according to another embodiment of the invention;

FIG. 5 presents a coating system for dispensing a solution on asubstrate according to another embodiment of the invention;

FIG. 6 depicts a method for dispensing a solution on a substrateaccording to a further embodiment of the invention; and

FIG. 7 depicts a computer system for implementing various embodiments ofthe invention.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

In the following description, in order to facilitate a thoroughunderstanding of the invention and for purposes of explanation and notlimitation, specific details are set forth, such as a particulargeometry of the dispensing system. However, it should be understood thatthe invention may be practiced in other embodiments that depart fromthese specific details.

Embodiments of the invention are described in detail below withreference to the accompanying drawings. As an embodiment according tothe present application, an apparatus for dispensing a resist solutionon a substrate utilized for a resist solution coating-developing systemin semiconductor manufacturing will be described below.

Referring now to the drawings, FIG. 1 is a schematic view showing aresist solution coating-developing system (or track system) according toone embodiment of the apparatus for dispensing a solution. As shown inFIG. 1, a resist solution coating-developing system 100 includes acassette station 20 in which first cassettes 21 a for storingunprocessed objects, e.g., substrates (or wafers W) and second cassettes21 b for storing processed substrates (or wafers W) are arranged inrespective predetermined positions. The cassette station 20 includes asubstrate transfer forceps 22 for loading and unloading substratesbetween cassettes 21 a and 21 b and a transfer table 23, a coatingprocessor 30 coupled to the cassette station 20 to form a resist film onthe surface of the substrate, a development processor 50 coupled to thecoating processor 30 with an interface unit 40 to develop the exposedsubstrate, and an exposure processor 70. The exposure processor 70 iscoupled to a development processor 50 via an interface unit 60 toirradiate ultraviolet light from a light source onto the coatedsubstrate through a predetermined mask member M and expose the resistfilm to a predetermined circuit pattern. The exposure processor 70includes cassette 73 for storing the mask member M to be placed upon theupper surface of a substrate, mask member transfer arm 72, substratetransfer arm 74, and substrate processing surface 71 (or table). Theinterface units 40 and 60 include transfer stations 61.

Linear transfer paths 81A and 81B extend in central portions of thecoating processor 30 and the development processor 50, respectively.Transfer mechanisms 82 and 83 are movable along the transfer paths 81Aand 81B, respectively. The transfer mechanisms 82 and 83 have substratearms 84 and 85, respectively, which can move in X and Y directions in ahorizontal plane and in a vertical direction (Z direction) and freelyrotate (θ).

On one side along the side edge of the transfer path 81A in the coatingprocessor 30, a brush cleaning unit 31, an adhesion/cooling unit 32which performs a hydrophobic treatment and in which an adhesion unit 32a and a cooling unit 32 b are stacked, and a baking unit 33 as a firstheating unit are arranged adjacent to each other along a line. On theother side of the transfer path 81A, a jet water cleaning unit 34 and anarbitrary number of, for example, two resist coating apparatuses 35 asfilm forming apparatuses are arranged adjacent to each other in a line.The resist coating apparatuses 35 can spin-coat substrates with varioustypes of resist solutions including a regular resist solution and anantireflection resist solution.

The baking unit 33 and the resist coating apparatuses 35 oppose eachother on the two sides of the transfer path 81A. Since the baking unit33 and the resist coating apparatuses 35 thus oppose each other at adistance on the two sides of the transfer path 81A, heat from the bakingunit 33 is prevented from being conducted to the resist coatingapparatuses 35. Consequently, when resist coating is performed theresist film can be protected from thermal influences. On one side alongthe side edge of the transfer path 82B in the developing processor 50,baking units 51 are arranged adjacent to each other along a line. On theother side of the transfer path 81B, developing units 52 are arrangedadjacent to each other along a line. The baking units 51 and developingunits 52 oppose each other at a distance on the two sides of thetransfer path 82B.

The resist solution coating-developing system can be configured forprocessing 248 nm resists, 193 nm resists, 157 nm resists, EUV resists,(top/bottom) anti-reflective coatings (TARC/BARC), and top coats.Additionally, for example, the resist solution coating-developing systemcan comprise a Clean Track ACT 8, or ACT 12 resist coating anddeveloping system commercially available from Tokyo Electron Limited(TEL).

FIG. 2 illustrates a coating system 200 including a coating chamber 210,a substrate holder 220 coupled to the coating chamber 210 and configuredto support substrate 225, and a solution nozzle assembly 230 configuredto dispense a solution, such as a resist solution. Additionally, thecoating system 200 includes a controller 250 coupled to the substrateholder 220 and the solution nozzle assembly 230, and configured toexchange data, information, and control signals with the substrateholder 220 and the solution nozzle assembly 230.

The substrate holder 220 is configured to rotate (or spin) substrate 225during dispensing of solution on the upper surface of substrate 225 fromthe solution nozzle assembly 230. A drive unit 222 coupled to thesubstrate holder 220 is configured to rotate the substrate holder 220.The drive unit 222 can, for example, permit setting the rotation rate,and the rate of acceleration of the substrate holder rotation.

The solution nozzle assembly 230 includes a single nozzle 232 positionedsubstantially near the center of substrate 225, and above an uppersurface thereof. The nozzle 232 is configured to dispense a solution,such as a 248 nm photo-resist solution, a 193 nm photo-resist solution,a 157 nm photo-resist solution, an EUV (extreme ultraviolet)photo-resist solution, or any other coating solution, such as a lowdielectric coating solution or a top/bottom anti-reflective coating(TARC/BARC) solution, on an upper surface of substrate 225 in adirection substantially perpendicular to the upper surface of substrate225. The nozzle 232 is coupled to an outlet end 236 of a control valve234. An inlet end 238 of control valve 234 is coupled to a solutionsupply system 240. The control valve 234 can be configured to regulatedispensing the solution on substrate 225. When open, the solution isdispensed upon the substrate 225. When closed, the solution is notdispensed upon the substrate 225. The solution supply system 240 caninclude at least one of a fluid supply valve 242, a filter 244, and aflow measurement/control device 246.

Additionally, nozzle 232 is configured to translate in a radialdirection from the center of substrate 225 to the peripheral edge ofsubstrate 225 using translation drive assembly 260, while dispensingsolution.

Additionally, controller 250 includes a microprocessor, memory, and adigital I/O port (potentially including D/A and/or A/D converters)capable of generating control voltages sufficient to communicate andactivate inputs to the drive unit 222 of substrate holder 220, thesolution nozzle assembly 230 (e.g., first control valve 234), solutionsupply system 240, and translation drive system 260 as well as monitoroutputs from these systems. A program stored in the memory is utilizedto interact with these systems according to a stored process recipe. Oneexample of controller 250 is a DELL PRECISION WORKSTATION 530™,available from Dell Corporation, Austin, Tex. The controller 250 mayalso be implemented as a general purpose computer such as the computerdescribed with respect to FIG. 7.

Controller 250 may be locally located relative to coating system 200, orit may be remotely located relative to the coating system 200 via aninternet or intranet. Thus, controller 250 can exchange data withcoating system 200 using at least one of a direct connection, anintranet, and the internet. Controller 250 may be coupled to an intranetat a customer site (i.e., a device maker, etc.), or coupled to anintranet at a vendor site (i.e., an equipment manufacturer).Furthermore, another computer (i.e., controller, server, etc.) canaccess controller 250 to exchange data via at least one of a directconnection, an intranet, and the internet.

The system described in FIG. 2 allows resist solution to be dispensedsubstantially at the center of the substrate and then at a radialdistance from the center of the substrate. The present inventors havediscovered that this technique allows a reduced shot size of resistsolution to be used to coat the substrate. Specifically, when a resistsolution is dispensed only at the center of the substrate, the wavefront may start out as a substantially circular shape. As the resistspreads across the full radial distance of the substrate however, thewave front may lose its circular shape and assume an irregular shapethat results in leading portions of the wave front arriving at theperimeter of the wafer before other portions. This results in wastedresist when the leading portions of the wave front wash over the edge ofthe substrate. The present inventors have discovered that dispensingresist first at a substantially center portion of the substrate and thenat a radial portion but within the wave front boundary provides bettercontrol of the resist wave front thereby allowing a smaller shot size.

Referring now to FIG. 3, a method for dispensing a solution on asubstrate using the system depicted in FIG. 2 is described. The coatingsystem 200 is configured to dispense the solution at a dispensing rate333 from nozzle 232. The dispensing rate 333 can be maintained constantduring solution dispensing, or it can be varied during solutiondispensing. While solution is dispensed on substrate 225, the substrateholder 220 is rotated at a rotation rate 344. The rotation rate 344 canbe maintained constant, or alternatively it can be varied duringsolution dispensing. Furthermore, during solution dispensing andsubstrate rotation, the solution spreads radially on the upper surfaceof substrate 225, wherein the solution wave front radially expands atfront speed 342. According to an embodiment of the invention, thetranslation drive assembly 260 radially translates the nozzle 232 at atranslation rate 340 that is substantially equivalent to or less thanthe front speed 342, as depicted by the phantom nozzle 334. For example,the translation rate 340 ranges from approximately 25% to approximately100% the front speed 342. Alternately, the translation rate 340 rangesfrom approximately 50% to approximately 100% the front speed 342.Alternately, the translation rate 340 ranges from approximately 75% toapproximately 100% the front speed 342. Alternately, the translationrate 340 ranges from approximately 90% to approximately 100% the frontspeed 342. Alternately, the translation rate 340 is substantiallyequivalent to the front speed 342.

According to another embodiment, FIG. 4 presents a coating system 400including a coating chamber 410, a substrate holder 420 coupled to thecoating chamber 410 and configured to support substrate 425, and asolution nozzle assembly 430 configured to dispense a solution, such asa resist solution. Additionally, the coating system 400 includes acontroller 450 coupled to the substrate holder 420 and the solutionnozzle assembly 430, and configured to exchange data, information, andcontrol signals with the substrate holder 420 and the solution nozzleassembly 430.

The substrate holder 420 is configured to rotate (or spin) substrate 425during dispensing of solution on the upper surface of substrate 425 fromthe solution nozzle assembly 430. A drive unit 422 coupled to thesubstrate holder 420 is configured to rotate the substrate holder 420.The drive unit 422 can, for example, permit setting the rotation rate,and the rate of acceleration of the substrate holder rotation.

The solution nozzle assembly 430 includes a nozzle array 432 having aplurality of nozzles 433 distributed radially above substrate 425 from,for example, the substrate center to the substrate edge. The nozzlearray 432 is configured to dispense a solution, such as a 248 nmphoto-resist solution, a 193 nm photo-resist solution, a 157 nmphoto-resist solution, an EUV (extreme ultraviolet) photo-resistsolution, or any other coating solution, such as a low dielectriccoating solution or a top/bottom anti-reflective coating (TARC/BARC)solution, on an upper surface of substrate 425 in a directionsubstantially perpendicular to the upper surface of substrate 425. Thenozzle array 432 is coupled to an outlet end 436 of a control valve 434.An inlet end 438 of control valve 434 is coupled to a solution supplysystem 440. The control valve 434 can be configured to regulatedispensing the solution on substrate 425. When open, the solution isdispensed upon the substrate 425. When closed, the solution is notdispensed upon the substrate 225. The solution supply system 440 caninclude at least one of a fluid supply valve 442, a filter 444, and aflow measurement/control device 446.

Referring still to FIG. 4, solution begins dispensing from the centernozzle in nozzle array 432 and proceeds to the second nozzle in nozzlearray 432 as the wave front of the solution on substrate 425 passes theradial location of the second nozzle. Thereafter, each nozzle beginsdispensing solution as the wave front passes its respective radiallocation. When solution begins dispensing from the next nozzle, itcontinues dispensing from the preceding nozzle. Alternatively, whensolution begins dispensing from the next nozzle, it discontinuesdispensing from the preceding nozzle. Thus, as with the embodiment ofFIG. 3, the configuration of FIG. 4 provides improved control over thewave front, which allows a reduced shot size of resist solution.

According to another embodiment, FIG. 5 illustrates a coating system 500including a coating chamber 510, a substrate holder 520 coupled to thecoating chamber 510 and configured to support substrate 525, and asolution nozzle assembly 530 configured to dispense a solution, such asa resist solution. Additionally, the coating system 500 includes acontroller 550 coupled to the substrate holder 520 and the solutionnozzle assembly 530, and configured to exchange data, information, andcontrol signals with the substrate holder 520 and the solution nozzleassembly 530.

The substrate holder 520 is configured to rotate (or spin) substrate 525during dispensing of solution on the upper surface of substrate 525 fromthe solution nozzle assembly 530. A drive unit 522 coupled to thesubstrate holder 520 is configured to rotate the substrate holder 520.The drive unit 522 can, for example, permit setting the rotation rate,and the rate of acceleration of the substrate holder rotation.

The solution nozzle assembly 530 includes a single nozzle 532 positionedsubstantially near the center of substrate 525, and above an uppersurface thereof. The nozzle 532 is configured to dispense a solution,such as a 248 nm photo-resist solution, a 193 nm photo-resist solution,a 157 nm photo-resist solution, an EUV (extreme ultraviolet)photo-resist solution, or any other coating solution, such as a lowdielectric coating solution or a top/bottom anti-reflective coating(TARC/BARC) solution, on an upper surface of substrate 525 in adirection substantially perpendicular to the upper surface of substrate525. Alternately, the solution nozzle assembly 530 includes a pluralityof nozzles as depicted in FIG. 4. The nozzle 532 is coupled to an outletend 536 of a control valve 534. An inlet end 538 of control valve 534 iscoupled to a solution supply system 540. The control valve 534 can beconfigured to regulate dispensing the solution on substrate 525. Whenopen, the solution is dispensed upon the substrate 525. When closed, thesolution is not dispensed upon the substrate 525. The solution supplysystem 540 can include at least one of a fluid supply valve 542, afilter 544, and a flow measurement/control device 546.

Additionally, nozzle 532 is configured to translate in a radialdirection from the center of substrate 525 to the peripheral edge ofsubstrate 525 using translation drive assembly 560, while dispensingsolution.

Referring still to FIG. 5, coating system 500 further includesdiagnostic system 570 for determining the radial location of the wavefront, the speed of the wave front, or the state of the wave front(e.g., stable wave front, or unstable wave front), or any combinationthereof. A stable wave front may be one having a substantially circularshape, while an unstable wave front may have an irregular shape asdiscussed above. The diagnostic system 570 can be used to assist incontrolling the wave front of the resist solution. The diagnostic system570 can include a light sensing system and an image capturing system.For example, the light sensing system can include a CCD (charge coupleddevice) camera, or a CID (charge injection device) camera for detectingthe progression of the solution wave front across substrate 525.Additionally, for example, the light sensing system can include a lightprojection device for providing background illumination of the solutionon the upper surface of substrate 525. Furthermore, for example, theimage capturing system can be configured to acquire and record images,and transmit these images to the controller 550 for determining the wavefront position, speed, and state.

Referring still to FIG. 5, controller 550 can, for instance, compute theposition of the wave front from frame to frame based upon the currentlocation of the wave front relative to a calibrated pixel array (e.g.,the pixel array for the camera set-up can be calibrated for position onthe substrate). Additionally, controller 550 can, for instance, computethe speed of the wave front from frame to frame based upon the number ofpixels elapsed (or passed) from one frame to the next divided by thetime elapsed from one frame to the next. Additionally, for instance,controller 550 can determine the state of the wave front, i.e., whetheror not the wave front includes a circular form spreading radially acrosssubstrate 525.

FIG. 6 presents a method of dispensing a solution on a substrateaccording to an embodiment of the invention. As illustrated in FIG. 6,the method includes a flow chart 600 beginning at 610 setting a processrecipe for solution dispensing. The process recipe can be designed for aspecific type of solution taking into account its fluid properties, suchas viscosity, surface tension, etc. Additionally, the process recipe canbe designed for a total volume of solution to be dispensed.

The process recipe can include one or more process parameters includingthe dispensing rate of solution as a function of time, the rotation rateof the substrate holder as a function of time, or the translation rateof the solution nozzle assembly as a function of time, or anycombination thereof. For example, the position or speed of the wavefront can be utilized to update any of these process parameters duringsolution dispensing. For instance, increasing the rotation rate canincrease the speed of the wave front, while decreasing the rotation ratecan decrease the speed of the wave front. Additionally, for instance,increasing the dispensing rate can increase the speed of the wave front,while decreasing the dispensing rate can decrease the speed of the wavefront.

In order to provide a uniform solution coating on the substrate for agiven total volume of solution, the one or more process parameters forthe process recipe can be determined using first principles fluidmechanic simulation, such as ANSYS, commercially available from ANSYSInc., Southpointe, 275 Technology Drive Canonsburg, Pa. 15317, FLUENT,commercially available from Fluent Inc., 10 Cavendish Ct. Centerra Park,Lebanon, N.H. 03766, or CFD-ACE+, commercially available from CFDResearch Corp., 215 Wynn Dr., Huntsville, Ala. 35805, or design ofexperiment (DOE) techniques, or monitoring and controlling the processin real-time using the diagnostic system described above for feedback,or any combination thereof.

According to an embodiment of the invention, the solution is dispensedabove the substrate at a radial location substantially equivalent to orless than the current location of the wave front. Therefore, the radialtranslation rate of the solution nozzle, or the rate the radial locationof solution dispensing is varied, is substantially equivalent to or lessthan the speed of the wave front. For example, the translation rateranges from approximately 25% to approximately 100% the front speed.Alternately, the translation rate ranges from approximately 50% toapproximately 100% the front speed. Alternately, the translation rateranges from approximately 75% to approximately 100% the front speed.Alternately, the translation rate ranges from approximately 90% toapproximately 100% the front speed. Alternately, the translation rate issubstantially equivalent to the front speed.

At 620, rotation of the substrate is initiated per the process recipe.The substrate rotation can have an acceleration phase such that thesubstrate rotation rate is increased from rest to a first pre-specifiedrate of rotation. Once the first pre-specified rotation rate isachieved, the rotation rate can be maintained invariant or varied.

At 630, the solution is dispensed from the solution nozzle assembly ontothe substrate for a first period of time. The dispensing of solutionfrom the solution nozzle assembly can be initiated coincident with therotation of the substrate. Alternately, the dispensing of solution fromthe solution nozzle assembly can be initiated after a delay in time.

At 640, the flow of solution from the solution nozzle assembly isterminated. The rate of rotation of the substrate can be maintainedconstant, or can be varied. For example, the rotation rate can beaccelerated or decelerated (during an acceleration or decelerationphase) to a third pre-specified rate of rotation. At 650, the rotationof the substrate is terminated. During this time, the rate of rotationis decreased to rest during a fourth period of time.

FIG. 7 illustrates a computer system 1201 for implementing variousembodiments of the present invention. The computer system 1201 may beused as the controller 450 to perform any or all of the functions of thecontroller described above. The computer system 1201 includes a bus 1202or other communication mechanism for communicating information, and aprocessor 1203 coupled with the bus 1202 for processing the information.The computer system 1201 also includes a main memory 1204, such as arandom access memory (RAM) or other dynamic storage device (e.g.,dynamic RAM (DRAM), static RAM (SRAM), and synchronous DRAM (SDRAM)),coupled to the bus 1202 for storing information and instructions to beexecuted by processor 1203. In addition, the main memory 1204 may beused for storing temporary variables or other intermediate informationduring the execution of instructions by the processor 1203. The computersystem 1201 further includes a read only memory (ROM) 1205 or otherstatic storage device (e.g., programmable ROM (PROM), erasable PROM(EPROM), and electrically erasable PROM (EEPROM)) coupled to the bus1202 for storing static information and instructions for the processor1203.

The computer system 1201 also includes a disk controller 1206 coupled tothe bus 1202 to control one or more storage devices for storinginformation and instructions, such as a magnetic hard disk 1207, and aremovable media drive 1208 (e.g., floppy disk drive, read-only compactdisc drive, read/write compact disc drive, compact disc jukebox, tapedrive, and removable magneto-optical drive). The storage devices may beadded to the computer system 1201 using an appropriate device interface(e.g., small computer system interface (SCSI), integrated deviceelectronics (IDE), enhanced-IDE (E-IDE), direct memory access (DMA), orultra-DMA).

The computer system 1201 may also include special purpose logic devices(e.g., application specific integrated circuits (ASICs)) or configurablelogic devices (e.g., simple programmable logic devices (SPLDs), complexprogrammable logic devices (CPLDs), and field programmable gate arrays(FPGAs)).

The computer system 1201 may also include a display controller 1209coupled to the bus 1202 to control a display 1210, such as a cathode raytube (CRT), for displaying information to a computer user. The computersystem includes input devices, such as a keyboard 1211 and a pointingdevice 1212, for interacting with a computer user and providinginformation to the processor 1203. The pointing device 1212, forexample, may be a mouse, a trackball, or a pointing stick forcommunicating direction information and command selections to theprocessor 1203 and for controlling cursor movement on the display 1210.In addition, a printer may provide printed listings of data storedand/or generated by the computer system 1201.

The computer system 1201 performs a portion or all of the processingsteps of the invention in response to the processor 1203 executing oneor more sequences of one or more instructions contained in a memory,such as the main memory 1204. Such instructions may be read into themain memory 1204 from another computer readable medium, such as a harddisk 1207 or a removable media drive 1208. One or more processors in amulti-processing arrangement may also be employed to execute thesequences of instructions contained in main memory 1204. In alternativeembodiments, hard-wired circuitry may be used in place of or incombination with software instructions. Thus, embodiments are notlimited to any specific combination of hardware circuitry and software.

As stated above, the computer system 1201 includes at least one computerreadable medium or memory for holding instructions programmed accordingto the teachings of the invention and for containing data structures,tables, records, or other data described herein. Examples of computerreadable media are compact discs, hard disks, floppy disks, tape,magneto-optical disks, PROMs (EPROM, EEPROM, flash EPROM), DRAM, SRAM,SDRAM, or any other magnetic medium, compact discs (e.g., CD-ROM), orany other optical medium, punch cards, paper tape, or other physicalmedium with patterns of holes, a carrier wave (described below), or anyother medium from which a computer can read.

Stored on any one or on a combination of computer readable media, thepresent invention includes software for controlling the computer system1201, for driving a device or devices for implementing the invention,and for enabling the computer system 1201 to interact with a human user(e.g., print production personnel). Such software may include, but isnot limited to, device drivers, operating systems, development tools,and applications software. Such computer readable media further includesthe computer program product of the present invention for performing allor a portion (if processing is distributed) of the processing performedin implementing the invention.

The computer code devices of the present invention may be anyinterpretable or executable code mechanism, including but not limited toscripts, interpretable programs, dynamic link libraries (DLLs), Javaclasses, and complete executable programs. Moreover, parts of theprocessing of the present invention may be distributed for betterperformance, reliability, and/or cost.

The term “computer readable medium” as used herein refers to any mediumthat participates in providing instructions to the processor 1203 forexecution. A computer readable medium may take many forms, including butnot limited to, non-volatile media, volatile media, and transmissionmedia. Non-volatile media includes, for example, optical, magneticdisks, and magneto-optical disks, such as the hard disk 1207 or theremovable media drive 1208. Volatile media includes dynamic memory, suchas the main memory 1204. Transmission media includes coaxial cables,copper wire and fiber optics, including the wires that make up the bus1202. Transmission media also may also take the form of acoustic orlight waves, such as those generated during radio wave and infrared datacommunications.

Various forms of computer readable media may be involved in carrying outone or more sequences of one or more instructions to processor 1203 forexecution. For example, the instructions may initially be carried on amagnetic disk of a remote computer. The remote computer can load theinstructions for implementing all or a portion of the present inventionremotely into a dynamic memory and send the instructions over atelephone line using a modem. A modem local to the computer system 1201may receive the data on the telephone line and use an infraredtransmitter to convert the data to an infrared signal. An infrareddetector coupled to the bus 1202 can receive the data carried in theinfrared signal and place the data on the bus 1202. The bus 1202 carriesthe data to the main memory 1204, from which the processor 1203retrieves and executes the instructions. The instructions received bythe main memory 1204 may optionally be stored on storage device 1207 or1208 either before or after execution by processor 1203.

The computer system 1201 also includes a communication interface 1213coupled to the bus 1202. The communication interface 1213 provides atwo-way data communication coupling to a network link 1214 that isconnected to, for example, a local area network (LAN) 1215, or toanother communications network 1216 such as the Internet. For example,the communication interface 1213 may be a network interface card toattach to any packet switched LAN. As another example, the communicationinterface 1213 may be an asymmetrical digital subscriber line (ADSL)card, an integrated services digital network (ISDN) card or a modem toprovide a data communication connection to a corresponding type ofcommunications line. Wireless links may also be implemented. In any suchimplementation, the communication interface 1213 sends and receiveselectrical, electromagnetic or optical signals that carry digital datastreams representing various types of information.

The network link 1214 typically provides data communication through oneor more networks to other data devices. For example, the network link1214 may provide a connection to another computer through a localnetwork 1215 (e.g., a LAN) or through equipment operated by a serviceprovider, which provides communication services through a communicationsnetwork 1216. The local network 1214 and the communications network 1216use, for example, electrical, electromagnetic, or optical signals thatcarry digital data streams, and the associated physical layer (e.g., CAT5 cable, coaxial cable, optical fiber, etc). The signals through thevarious networks and the signals on the network link 1214 and throughthe communication interface 1213, which carry the digital data to andfrom the computer system 1201 maybe implemented in baseband signals, orcarrier wave based signals. The baseband signals convey the digital dataas unmodulated electrical pulses that are descriptive of a stream ofdigital data bits, where the term “bits” is to be construed broadly tomean symbol, where each symbol conveys at least one or more informationbits. The digital data may also be used to modulate a carrier wave, suchas with amplitude, phase and/or frequency shift keyed signals that arepropagated over a conductive media, or transmitted as electromagneticwaves through a propagation medium. Thus, the digital data may be sentas unmodulated baseband data through a “wired” communication channeland/or sent within a predetermined frequency band, different thanbaseband, by modulating a carrier wave. The computer system 1201 cantransmit and receive data, including program code, through thenetwork(s) 1215 and 1216, the network link 1214, and the communicationinterface 1213. Moreover, the network link 1214 may provide a connectionthrough a LAN 1215 to a mobile device 1217 such as a personal digitalassistant (PDA) laptop computer, or cellular telephone.

Although only certain exemplary embodiments of this invention have beendescribed in detail above, those skilled in the art will readilyappreciate that many modifications are possible in the exemplaryembodiments without materially departing from the novel teachings andadvantages of this invention. Accordingly, all such modifications areintended to be included within the scope of this invention.

Hence, numerous modifications and variations of the present inventionare possible in light of the above teachings. It is therefore to beunderstood that within the scope of the appended claims, the inventionmay be practiced otherwise than as specifically described herein. Forexample, other configurations of the solution nozzle assembly and otherprocesses may be used to dispense the solution on the substrate.

1. A method of dispensing a solution on a substrate comprising: rotatingsaid substrate; translating a nozzle from the center of said substratetowards a peripheral edge of said substrate; dispensing said solutionfrom said nozzle on said substrate during said translating in order toform a wave front that spreads radially across the upper surface of saidsubstrate, wherein said solution initially dispenses at the center ofsaid substrate and progresses to dispense at a radial location away fromthe center of said substrate; adjusting a rotation rate for saidrotating during said dispensing; terminating said dispensing of saidsolution; and terminating said rotating of said substrate.
 2. The methodof claim 1, wherein said solution comprises a 248 nm (nanometer)photo-resist solution, a 193 nm photo-resist solution, a 157 nmphoto-resist solution, an EUV (extreme ultraviolet) photo-resistsolution, an anti-reflective coating solution, a low dielectric coatingsolution, and a top coat solution.
 3. The method of claim 1, whereinsaid translating said nozzle is such that said radial location of saiddispensing is substantially equivalent to or less than a radial positionof said wave front at any instant in time.
 4. The method of claim 1,further comprising: adjusting a radial translation rate of said nozzle.5. The method of claim 1, further comprising: adjusting a dispensingrate of said solution.
 6. The method of claim 1, wherein said adjustingsaid rotation rate is performed in accordance with a process recipe, asimulation of said dispensing, or feedback from a diagnostic system, orany combination of two or more thereof.
 7. The method of claim 1,further comprising: setting a process recipe in order to achieve saiddispensing, wherein said process recipe is designed for a total volumeof said solution to dispense, and said process recipe includes adispensing rate from said nozzle, said rotation rate for said substraterotation, and a radial translation rate of said nozzle.
 8. The method ofclaim 1, wherein said nozzle is configured to provide said dispensing atsaid radial location ranging from approximately 25% to 100% of a radialposition of said wave front.
 9. The method of claim 1, wherein saidnozzle is configured to provide said dispensing at said radial locationranging from approximately 50% to 100% of a radial position of said wavefront.
 10. The method of claim 1, wherein said nozzle is configured toprovide said dispensing at said radial location ranging fromapproximately 90% to 100% of a radial position of said wave front. 11.The method of claim 1, wherein said nozzle is configured to provide saiddispensing at said radial location that is substantially equivalent to aradial position of said wave front.
 12. The method of claim 1, whereinsaid dispensing translates radially at a translation rate substantiallyequivalent to or less than a speed of said wave front.
 13. The method ofclaim 12, wherein said translation rate ranges from approximately 25% to100% of said speed of said wave front.
 14. The method of claim 12,wherein said translation rate ranges from approximately 90% to 100% ofsaid speed of said wave front.
 15. A method of dispensing a solution ona substrate comprising: selecting a process recipe comprising one ormore process parameters for dispensing said solution, said one or moreprocess parameters including a dispensing rate of said solution as afunction of time, a rotation rate of said substrate as a function oftime, and a translation rate of a nozzle for dispensing said solution asa function of time; rotating said substrate; translating said nozzlefrom the center of said substrate towards a peripheral edge of saidsubstrate; dispensing said solution from said nozzle on said substratein order to form a wave front that spreads radially across the uppersurface of said substrate, wherein said solution initially dispenses atthe center of said substrate and progresses to dispense at a radiallocation of said substrate away from the center; and adjusting saiddispensing, said rotating, and said translating according to saidprocess recipe.
 16. The method of claim 15, further comprising:measuring a position of said wave front, a speed of said wave front, ora state of said wave front, or any combination of two or more thereof;and updating any one of said process parameters using said measuring.17. A method of dispensing a solution on a substrate comprising:rotating said substrate; translating a nozzle from the center of saidsubstrate towards a peripheral edge of said substrate; dispensing saidsolution from said nozzle on said substrate in order to form a wavefront that spreads radially across the upper surface of said substrate,wherein said solution initially dispenses at the center of saidsubstrate, and progresses to dispense at a radial location away from thecenter; controlling a shape of said wave front; terminating saiddispensing of said solution; and terminating said rotating of saidsubstrate.
 18. The method of claim 17, wherein said controllingcomprises performing any combination of one or more of the following:adjusting a rotation rate for said rotating; adjusting a radialtranslation rate of the nozzle; or adjusting a dispensing rate of saidsolution.
 19. A coating system for dispensing a solution on a substrate,comprising: a coating chamber; a substrate holder coupled to saidcoating chamber and configured to support said substrate; a drive unitcoupled to said substrate holder and configured to rotate said substrateholder; a nozzle coupled to said coating chamber and configured todispense said solution on said substrate to form a wave front thatspreads radially across the upper surface of said substrate; atranslation drive system coupled to said nozzle and configured totranslate said nozzle from the center of said substrate towards aperipheral edge of said substrate; a solution supply system coupled tosaid nozzle and configured to supply said nozzle with said solution; anda controller coupled to said drive unit, said translation drive system,and said solution supply system, and configured to controllably adjust arotation rate for rotating said substrate holder, or a translation ratefor translating said nozzle, or a combination thereof.
 20. The coatingsystem of claim 19, wherein said controller is further configured tocontrollably adjust a dispensing rate for dispensing said solution fromsaid nozzle.
 21. A computer-readable medium encoded with a computerprogram, wherein the program, when executed by a processor, causes theprocessor to perform a method comprising: rotating said substrate;translating a nozzle from the center of said substrate towards aperipheral edge of said substrate; dispensing said solution from saidnozzle on said substrate during said translating in order to form a wavefront that spreads radially across the upper surface of said substrate,wherein said solution initially dispenses at the center of saidsubstrate and progresses to dispense at a radial location away from thecenter of said substrate; adjusting a rotation rate for said rotatingduring said dispensing; terminating said dispensing of said solution;and terminating said rotating of said substrate.